Vinyl halide polymer products have many structural applications useful in construction and transportation. Many uses are made of plasticized vinyl chloride polymers as in fabrics, upholstery, wall covering and the like where flame resistance and smoke formation could be a problem. Government and safety regulations relating to such materials are now in effect. Not only is flame resistance to be reduced in such materials as vinyl chloride plastic products, but smoke generated by vinyl chloride polymer products both in fires and in a smoldering state also must be reduced. There is need for improved plastic products which are safer in fire situations, even for vinyl chloride polymers which generally are considered to be flame resistant. A number of materials have been proposed and used in polyvinyl chloride for this purpose, but very few have been found to be completely satisfactory. Many are not compatible or readily mixed with vinyl chloride polymers, many are colored or form colored products in vinyl chloride polymer compositions and many have adverse effects on processing and the physical properties of vinyl chloride polymers.
U.S. Pat. Nos. 3,821,151 and 3,870,679 disclose the use of certain molybdenum compounds in PVC. The specific compounds listed suffer from the disadvantages that many such as commercially available MoO.sub.3, are colored compounds giving an unsatisfactory pigmentation color to compositions in which they are used.
U.S. Pat. No. 3,845,001 discloses and claims the use of copper compounds such as Cu.sub.2 O mixed with MoO.sub.3 and reduced smoke production during combustion. This patent also states that "the applicability of such oxides suggests the use of other compounds" such as the salts of carboxylic acids as the acetates and butyrates and organo compounds such as copper carbonyl. While cuprous oxide and molybdenum oxide reduce the smoke produced during the combustion of polyvinyl chloride, other problems are introduced. Cu.sub.2 O results in an undesirable red color in the compounds. The copper caboxylates that are suggested in U.S. Pat. No. 3,845,001 are generally unsatisfactory from other viewpoints than smoke reduction, for example, cupric formate during milling into polyvinyl chloride causes discoloration and black spots. This coloration problem is particularly acute with the tin sulfur stabilizers used widely throughout the industry. Further, copper formate, copper acetate and copper sulfide cause degradation of polyvinyl chloride.